Fence panel

ABSTRACT

A fence panel is provided that includes a first set of horizontal parallel spaced apart wires sandwiched between a second and third set of vertical wires spot-welded to either side of the first set of wires. At least some of the individual wires of the second set are opposite wires of the third set to form adjacent pairs of vertical wires. The wires are made from high tensile steel with a diameter of between 2 and 8 mm and the elements of the second and third sets are spaced apart 3 to 10 times as far as the elements of the first set of wires. The fence panel has a length of about 3 m, height of about 3m and weight of about 10.5 kg/M 2 .

FIELD OF THE INVENTION

This invention relates to a fence panel and, more particularly, to afence panel of a grid-like construction.

BACKGROUND TO THE INVENTION

Fences used in and around prisons, highways, airports and the like mustprovide good visibility therethrough, even when viewed at an acuteangle, and must be robust enough so as not to be easily breached.

Fences of a grid-like construction with vertical wires spaced relativelyfar apart in relation to horizontal wires are known. Such aconfiguration generally allows good visibility through the fence.However, a fence constructed of a single set of vertical and horizontalwires may not be robust enough.

Grid fences of the type described above, but where pairs of adjacenthorizontal wires are fixed on opposite sides of the uprights, are alsoknown. These fences, however, have been known to be broken by insertinga lever between pairs of horizontal wires and prising them apart. Theycan also be breached by severing a number of adjacent uprights at thesame horizontal level and biasing the broken ends apart to create a gap.Finally, these fences have also been known to topple when stronghorizontal forces, such as powerful winds, occur, and generally requirea lot of material for their construction, making them relativelyexpensive and heavy.

In this specification any reference to the “horizontal” or “vertical”orientation of an element, wire or fence panel will be understood torefer to the fence panel in its operative upright position.

OBJECT OF THE INVENTION

It is an object of this invention to provide a fence panel that, atleast partially, alleviates some of the abovementioned problems.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a fence panelcomprising a first set of horizontal parallel elongate elements spacedapart to form a panel having first and second sided; a second set ofvertical parallel elongate elements fixed to the first side of thepanel; and a third set of vertical parallel elongate elements fixed tothe second side of the panel, wherein at least some of the elements ofthe third set are opposite elements of the second set to form adjacentpairs of vertical elongate elements.

Further features of the invention provide for the second set of elementsand the third set of elements to be spot-welded to the first set ofelements; for the elongate elements to be high tensile steel wire; andfor the steel wire to have a diameter of between 2 mm and 8 mm.

Still further features of the invention provide for the second set ofelements to be spaced apart 3 to 10 times as far as the first set ofelements; and for the first set of elements to be spaced about 13 mmapart and the second set of elements to be spaced about 76 mm apart.

The fence panel may have a length of about 3 m, a height of about 3 m;and a weight of about 10.5 kg/m².

According to one aspect of the invention the third set of elongateelements may extend partway along the height of the panel and the firstset extend along the full height of the panel to form a fence panelhaving single vertical elongate elements at its operatively uppersection and pairs of vertical elongate elements at its operatively lowersection.

The invention extends to a fence including a plurality of fence panelsaccording to the invention supported by uprights.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example only, withreference to the drawings in which:

FIG. 1 is a perspective view and an end view a prior art fence panel;

FIG. 2 is a perspective view of a second prior art fence panel;

FIG. 3 is a perspective view and an end view of a third prior art fencepanel;

FIG. 4 is a perspective view of the fence panel of FIG. 2 with two wirescut to form a breach; and

FIG. 5 is a perspective view of a fence panel in accordance with theinvention.

DETAILED DESCRIPTION OF THE DRAWINGS

It will be understood that the fence panels described may be supportedby various structures, including upright steel poles or concretepillars. Such structures are well-known and are not described herein.

FIG. 1 shows a prior art fence panel (1). The fence panel (1) has afirst set of parallel spaced apart wires (2) that form a panel with afirst side (4) and a second side (6). A second set of parallel spacedapart wires (8) extend on the first side (4) normally to the first setof wires (2). The second set of wires (8) are spaced apart substantiallyfurther than the first set of wires (2), so that when the fence panel(1) is erected in the orientation shown with the first set of wires (2)extending horizontally, an object (10) is visible through the fencepanel (1), even when a viewer (12) is at an acute angle thereto.

FIG. 2 shows a second prior art fence panel (20), of a similarconstruction to the fence panel (1) in FIG. 1, but which has beenreinforced with additional wies. The fence panel (20) has a first side(24) and a second side (26). A first set of parallel spaced apart wires(22) extend on the second side (26), a second set of spaced apartparallel wires (28) extend normally to the first set of wires (22) and athird set of wires (22) and a third set of parallel spaced apart wires(30) extend in parallel with the first set (22) on the first side (24)so that the second set of wires (28) and sandwiched between the firstset (22) and the third set (30). Individual wires of the first set (22)and the third set (30) are aligned so that they form adjacent pairs ofwires (32) on opposite sides (24, 26) of the panel. The weight of thefence panel (20) is typically in the order of 17.3 Kg/m².

The fence panel (20) shown in FIG. 2 is more robust than the fence panel(1) of FIG. 1. There are more wires to cut and it is also more difficultto cut the pairs of wires (32) with a wire cutter.

However the fence panel (20) of FIG. 2 has a particular disadvantage. Asshown in FIG. 2, the fence panel (20) can be broken by inserting alever, such as a screwdriver or, in this case, a crowbar (34) betweenpairs of wires (32) and prising them apart. The fence panel (20) alsouses substantially more wire than the panel (1) in FIG. 1, making itheavier and more expensive to manufacture.

FIG. 3 shows a third prior art fence panel (40) of similar constructionto the fence panel (20) of FIG. 2, but where one side (44) of the panel(40) has wires (42) that are spaced apart more widely than the wires(48) on the opposite side (46) of the panel (40). This fence panel (40)uses less material than the fence panel (20) in FIG. 2, but isproportionately weaker and can also be broken using a screwdriver orcrowbar (34) in the manner illustrated in FIG. 2. The weight of thefence panel (40) is typically in the order of 10.9 Kg/M².

FIG. 4 shows the fence panel (20) of FIG. 2 which has been breached bysevering a number of adjacent wires of the second set of wires (28) at alevel in line with an element of the first set of wires (22). The brokensections have been biased apart to create a gap (29). The fence panel(1) of FIGS. 1 and 3 can also be similarly breached. Such a breach canbe created at a lower end of the fence panel where it is difficult todetect by security personnel. Individual elements of the second set ofwires (28) can be cut over a period of time to make the breach evenharder to detect.

FIG. 5 shows a fence panel (50) in accordance with the invention. Thefence panel (50) has a first set of horizontal spaced apart parallelwires (52) that form a panel with a first side (54) and a second side(56). A second set of vertical parallel spaced apart wires (58) arespot-welded to the second side (54) and a third set of vertical parallelspaced apart wires (60) are spot-welded to the second side (56) of thepanel. Individual wires of the second set of wires (58) and the thirdset of wires (60) are aligned opposite each other to form pairs ofadjacent vertical wires (62). The spacing between the individual wiresof the second and third set of wires (58, 60) is typically about 76 mm,while the spacing between individual wires of the first set of wires(52) is about 13 mm. The wires are high-tensile steel wire having adiameter of about 4 mm and are spot-welded together.

The typical weight of a fence panel shown in FIG. 5 has been found to beabout 10.5 kg/M². By contrast, the weight of the panel shown in FIG. 3was found to be about 10.9 kg/M² while the weight of the panel shown inFIGS. 2 and 4 was found to be about 17.3 kg/M². The pairs of wires (58)in the panel (50) of FIG. 5 can also not be easily levered apart,because the gap (64) in which a lever would be wedged is typically toosmall to admit a crowbar, screwdriver or other effective leveringdevice. The panel (50) of FIG. 5 is also more difficult to breach in themanner illustrated in FIG. 4, because the first and second wires (60,62) would both have to be severed, and because the wires (60, 62)provide additional rigidity against being bent in the manner illustratedin FIG. 4. Finally, when erected in the configuration shown in FIG. 5where the first and second wires (60, 62) extend vertically, these wiresprovide additional support against horizontal forces, such as strongwinds, that tend to topple the fence panel (50). The fence panel (50)shown in FIG. 5 can therefore be erected within a support structure (notshown) which is cheaper that the support structure required for theprior art fence panels referred to above.

Intersecting wires of the fence panel can be welded together by means ofa mechanical hand operated process or by means of a semi of fullyautomated process.

The invention therefore provides a fence panel or relatively lightweightconstruction, having elongate elements that cannot easily be broken bybeing prised apart with a lever, which is of a relatively robustconstruction and does not easily topple and which provides goodvisibility through the fence panel when viewed at an acute angle.

It will be appreciated that other embodiments of a fence panel may bedevised that fall within the scope of the invention, especially asregards the exact configuration thereof. For example, it is notnecessary for the second set of elements to all be in pairs. Aconfiguration with every third element in pairs with two single wiresbetween every pair could be used.

The fence panel can also have pairs of adjacent vertical elongateelements at its operatively lower section and single vertical elongateelements of the second set at the operatively upper section of the fencepanel. It has been found that breaches in security fences normally occurat eye level or lower. This section can therefore be constructed asdescribed in the invention, while the higher part of the fence panel canbe constructed with only two sets of wires, similar to the fence panelshown in FIG. 1.

The fence panel (50) will typically have a width of about 3 metres and aheight of 3 metres or higher, up to about 6 metres.

1. A fence panel comprising: a first set of horizontal parallel elongateelements spaced apart to form a panel having first and second sides; asecond set of vertical parallel elongate elements fixed to the firstside of the panel; and a third set of vertical parallel elongateelements fixed to the second side of the panel; wherein at least some ofthe elements of the third set are opposite elements of the second set toform adjacent pairs of vertical elongate elements.
 2. A fence panel asclaimed in claim 1 in which the second set of elements and the third setof elements are spot-welded to the first set of elements.
 3. A fencepanel as claimed in claim 1 in which the elongate elements are hightensile steel wire.
 4. A fence panel as claimed in claim 3 in which thesteel wire has a diameter of between 2 mm and 8 mm.
 5. A fence panel asclaimed in claim 1 in which the second set of elements are spaced apart3 to 10 times as far as the first set of elements.
 6. A fence panel asclaimed in claim 5 in which the first set of elements are spaced about13 mm apart and the second set of elements are spaced about 76 mm apart.7. A fence panel as claimed in claim 1 having a length of about 3 m anda height of about 3 m.
 8. A fence panel as claimed in claim 1 having aweight of about 10.5 kg/m².
 9. A fence panel as claimed in claim 1 inwhich the third set of elongate elements extends partway along theheight of the panel and the first set extends along the full height ofthe panel to form a fence panel having single vertical elongate elementsat its operatively upper section and pairs of vertical elongate elementsat its operatively lower section.
 10. A fence including a plurality offence panels as claimed in claim 1 supported by uprights.
 11. (canceled)